000 AGXX40 KNHC 121638 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1238 PM EDT SUN APR 12 2015 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. MEDIUM- HIGH CONFIDENCE...EXCEPT MEDIUM CONFIDENCE AFTER DAY 4. LOW LEVEL SOUTHERLY RETURN FLOW AND DIFFLUENT UPPER FLOW CONTINUES ACROSS THE NORTHERN GULF PRODUCING SCT RW/ISOL TS WITH EMBEDDED AREAS 3-5 NM VSBY IN PATCHY FOG OVER THE NW WATERS...ALL DENOTED IN THE WEATHER GRIDS. A N-S TROUGH IS QUICKLY DISSIPATING OVER THE CENTRAL BAY OF CAMPECHE ACCOMPANIED BY A E-SE 10-15 KT WIND SHIFT. SE 10-15 KT FLOW HAS SET UP ELSEWHERE ACROSS THE GULF WATERS. EXPECT THIS EVENINGS THERMAL ENHANCEMENT ALONG THE NW COAST OF THE YUCATAN PENINSULA TO BE IN THE 20-25 KT RANGE...WITH SE 20-25 KT WINDS THEN PROPAGATING W ACROSS THE S-CENTRAL GULF ON MON MORNING. ALTHOUGH MON EVENINGS THERMAL ENHANCEMENT WILL NOT BE AS STRONG AS THIS EVENINGS...STILL EXPECT SE 20-25 KT FLOW TO DEVELOP ACROSS THE WATERS S OF 26N BETWEEN 87W-93W ON TUE MORNING. TUE EVENINGS THERMAL ENHANCEMENT WILL BE WEAKER THAN MON EVENINGS...AND WED EVENINGS WILL BE WEAKER THAN TUE EVENINGS...AND SO FORTH WITH ONLY A MINOR ENHANCEMENT ALONG THE N COAST OF THE YUCATAN PENINSULA ON FRI EVENING. FURTHER N THE GRADIENT WILL WEAKEN CONSIDERABLY ON WED AHEAD OF A WEAK COLD FRONT MOVING SE INTO THE NW WATERS ON THU. THE FRONT IS EXPECTED TO STALL OVER THE NW GULF ON THU NIGHT INTO FRI. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS WITH MANUAL ADJUSTMENTS PER ALTIMETER DATA ACROSS THE TROPICAL ATLC WATERS. MEDIUM-HIGH CONFIDENCE. ATLC RIDGING N OF THE AREA...COMBINED WITH LOW PRES OVER NW COLOMBIA...WILL SUPPORT NEAR GALE 25-30 KT NE WINDS WITHIN 90- 120 NM OF THE COAST OF COLOMBIA TONIGHT AND AGAIN ON MON NIGHT ...THEN DIMINISHING TO 20-25 KT MAXIMUM CONDITIONS EACH NIGHT BEGINNING ON TUE NIGHT AS THE ATLC RIDGE GRADUALLY WEAKENS. STRONG TRADES EXPECTED ELSEWHERE ACROSS THE CENTRAL CARIBBEAN TONIGHT AND MON NIGHT...THEN THE GRADIENT WILL RELAX THROUGH THE END OF THE PERIOD. E TRADES WILL INCREASE TO 20-25 KT ACROSS THE GULF OF HONDURAS EACH NIGHT WITH SEAS BUILDING TO 8 FT. FRESH TRADES WITH SEAS OF 5-8 FT EXPECTED ACROSS THE TROPICAL N ATLC WATERS THROUGH THE PERIOD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE. AN E-W RIDGE EXTENDS FROM 30N55W TO 27N70W. A COLD FRONT EXTENDS FROM 31N65W TO 29N74W WHERE IT BECOMES STATIONARY WESTWARD TO NE FL. THE RIDGE WILL RETRACT E TONIGHT WITH THE COLD FRONT REACHING FROM 31N59W TO 29N65W THEN BECOMING A FRONTAL TROUGH CONTINUING WNW TO SE GA AT SUNRISE ON MON. THE COLD FRONT SEGMENT WILL PASS E OF 55W ON TUE WHILE THE FRONTAL TROUGH PORTION LIFTS N OF 31N AS A RIDGE REBUILDS FROM BERMUDA TO PORT CANAVERAL. THE RIDGE WILL RETREAT E AGAIN ON TUE NIGHT IN ADVANCE OF THE NEXT COLD FRONT MOVING OFF THE SE GA COAST ON TUE NIGHT...THEN ACCELERATING E REACHING FROM 31N60W TO 29N71W EARLY WED WITH THE W PORTION OF THE FRONT STALLING BRIEFLY ACROSS THE FAR NORTHERN WATERS W OF 71W. THE NORTHERLY FLOW WILL INCREASE TO 20-25 KT N BETWEEN THE FRONT AND 75W LATE WED NIGHT INTO EARLY THU. THERE IS STILL SOME POSSIBILITY OF A WEAK FRONTAL WAVE LOW BRIEFLY DEVELOPING JUST OFF THE NE FL COAST ALONG THE STATIONARY FRONT ON THU. THE POST FRONTAL RIDGE WILL BRIDGE THROUGH THE FRONTAL REMNANTS ON FRI. TUTT INDUCED LOW-MID LEVEL INVERTED TROUGHS CONTINUE TO DEVELOP S OF THE SURFACE RIDGE AND PROPAGATE W ACROSS THE AREA... ACCOMPANIED BY MOSTLY SHALLOW CONVECTION...BUT GENERALLY DISSIPATING BEFORE REACHING THE BAHAMAS AS THE TROUGHS ENCOUNTER LESS FAVORABLE UPPER SUPPORT W OF 62W. THE GRADIENT SUPPORTS 15- 20 KT TRADES S OF 23N...EXCEPT ENHANCED TO 20-25 KT ALONG THE N COAST OF HISPANIOLA AND ATLC APPROACH TO THE WINDWARD PASSAGE...DURING THE AFTERNOONS INTO THE EARLY NIGHT HOURS...WITH SEAS BUILDING TO 8 FT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER NELSON. NATIONAL HURRICANE CENTER.